نتایج جستجو برای: zr mcm 41

تعداد نتایج: 102987  

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده علوم پایه 1391

نانو تکنولوژی رشته ای است که به سرعت در حال پیشرفت است و شامل ساخت و استفاده از مواد و تجهیزات در مقیاس نانو می باشد. مواد مختلفی حاوی ترکیبات نانو نقش مهمی در علم و فناوری نوین از جمله علم داروسازی ایفا می کند. mcm-41 یکی از مواد مزوپور امزوزه به عنوان حامل دارو بکار می رود.مواد آرایش یافته mcm-41 دارای شبکه ای از مجراها و فضاهای تهی با اندازه مناسب در مقیاس نانو (nm50-2 ) است.ساختار این منفذ...

Journal: :Environmental science & technology 2013
Liang-Yi Lin Hsunling Bai

An efficient and economic approach is proposed for the fast and direct recovery of silica materials from photonic waste powder. Unlike the conventional alkaline fusion method for the extraction of silica from waste materials, this method possesses advantages of a rapid and low-energy-consumed process with total recovery yield. The obtained mesoporous silica material, denoted as MCM-41(DU)-F, wa...

2006
Edwin Alarcón Aída Luz Villa Consuelo Montes de Correa

Introduction Nopol is an unsaturated alcohol useful for the synthesis of fragrances, pesticides and household products [1]. It has been traditionally obtained by condensation of β-pinene and paraformaldehyde at high temperatures or using homogeneous Lewis acid catalysts [2]. Recently, heterogeneous catalysts: FePO4, Sn-MCM-41 and Zn-Al-MCM-41, have been reported for nopol synthesis under mild c...

2013
Hyeonhee Choi Jung-Hyun Bae Do Heui Kim Young-Kwon Park Jong-Ki Jeon

MCM-41 was used as a support and, by using atomic layer deposition (ALD) in the liquid phase, a catalyst was prepared by consecutively loading titanium oxide and vanadium oxide to the support. This research analyzes the effect of the loading amount of vanadium oxide on the acidic characteristics and catalytic performance in the dehydration of butanol. The physical and chemical characteristics o...

2017
Wenjie Zhu Jingxuan Wang Di Wu Xitong Li Yongming Luo Caiyun Han Wenhui Ma Sufang He

Mesoporous silica materials (MSMs) of the MCM-41 type were rapidly synthesized by microwave heating using silica fume as silica source and evaluated as adsorbents for the removal of Cu2+, Pb2+, and Cd2+ from aqueous solutions. The effects of microwave heating times on the pore structure of the resulting MSMs were investigated as well as the effects of different acids which were employed to adju...

Journal: :Chemical communications 2015
Xi-Jie Lin Ai-Zhi Zhong Yong-Bin Sun Xing Zhang Wei-Guo Song Rong-Wen Lu An-Min Cao Li-Jun Wan

Pd nanoparticles were successfully introduced into the channels of mesoporous silica MCM-41 with their dispersion well-tuned. We identified the dual role played by CTAB, which was critical for both the micelle template and Pd grafting, leading to the formation of a highly active Pd-MCM-41 nanocomposite for catalysing the Suzuki reaction.

2005
Susmit Basu Himadri Paul Chinnakonda S. Gopinath Sumit Bhaduri Goutam Kumar Lahiri

Anionic platinum carbonyl cluster has been ion paired with cinchonidium groups that are chemically bound to the surface of MCM-41 and fumed silica. In the hydrogenation of methyl pyruvate or acetophenone the fumed silica-based catalyst gives zero enantioselectivity, but under optimum conditions enantiomeric excesses of > 90 and ∼ 40%, respectively, are obtained with the MCM-41-based catalyst.

2008
N. Kazemi F. Farzaneh

Ti-MCM-41 was synthesized at pH 3, 7 and 11. The titanium content was determined by AAS and found to be 4%, 3.2% and 4.5%, respectively. In order to increase the titanium content in Ti-MCM-41, Ti(IV) ions were grafted onto TiMCM-41 using TiCl4 in toluene and Ti(OBu)4 in ethanol. The incorporation of Ti was determined to be 28% and 30%, respectively. The oxidation of olefins such as cyclopentene...

Journal: :Catalysts 2021

The development of selective and robust heterogeneous oxidation catalysts is an enabling technology for conversion biomass-derived platform chemicals. Vanadium active sites were incorporated into the structure mesoporous silica via ultra-fast, one-pot synthesis method based on microwave-assisted heating. In addition, Al/Ti/Zr/Ce anchoring ions introduced in order to minimize vanadium leaching b...

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